The increasing demand for bandwidth has resulted in a need for equipment which can transmit both telephony and data signals from telephone central offices to subscriber residences and businesses. Because of the tremendous number of twisted wire pairs which are in place for the delivery of traditional phone services, telecommunications manufacturers have developed digital subscriber loop transmission systems which support the transport of digital data from telephone central offices to subscribers. Such systems offer the advantage that they can make use of the existing twisted wire pairs, although it is sometimes necessary to place electronics for sending and receiving these signals outside of the telephone central office and closer to the subscribers.
Digital subscriber loop systems offer the advantage of being able to provide data signals to subscribers, and in many instances allow traditional telephone services to be transmitted simultaneously with a digital signal. This allows the subscriber to have a primary phone line along with a high-speed digital data service.
However, if a twisted wire pair is being used to simultaneously provide a traditional analog phone service and high-speed data it cannot be used to provide additional phone lines using existing digital subscriber loop systems. This requires that a separate twisted wire pair be used if the subscriber wants to have a second phone line in addition to the primary phone line and high-speed data service.
For the foregoing reasons, there is a need for a method and apparatus which can provide analog phone service in a residence or business in a digital subscriber loop access system.